Explosive storehouse construction

ABSTRACT

An explosive storehouse comprising a head wall, a rear wall, two side walls and a single span arched roof;
         wherein the head wall, rear wall, two side walls and the single span arched roof all include a metal lining located internally of the earth covered magazine explosive storehouse; and   wherein at least the two side walls, rear wall and the single span arched roof include shotcrete.

RELATED APPLICATION

This application claims priority from Australian Application Number 2018901356 filed Apr. 24, 2018, the entire disclosure of which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention generally relates to an explosive storehouse design.

BACKGROUND OF THE INVENTION

Explosive storehouses are specially designed to minimise the damaging effect of munitions housed in the explosive storehouse exploding. Consequently, explosive storehouses are designed to localise the blast radius around an explosive storehouse. This minimises the chances of an explosion in one explosive storehouse triggering sympathetic detonation to adjacent explosives storehouse. It also limits the distance debris from the explosion travels, putting people and property at risk.

In existing explosive store houses, the roof and walls are reinforced to help minimise the effect of an explosion. In existing explosive store houses the roofing and side walls are also commonly covered in a mound of dirt to assist with minimising the effect of an explosion. These types of explosive storehouses are known as an ESH.

Another common feature in existing explosive storehouses that are ESH is a reinforced arched roof. This assists in minimising the effect of an explosion partially due to the geometry of the reinforced arch and the strength it provides. An arch also allows the roof to be large and single span. For efficiency, in explosive storehouses the arched roof typically extends to the floor and no separate walls are present. These explosive storehouses with an arched roof extending to the floor include a significant amount of floor space that cannot be used due to the height of objects and accessibility with transportation such as forklifts.

There also exist explosive storehouses with straight walls and an arched roof. These include Stradley type explosive storehouses and Freloc-Stradley type explosive storehouses. These types of structures are made of poured reinforced concrete that is cast to be freestanding. The walls of the Stradley and Freloc-Stradley type explosive storehouses are typically concrete.

Reference to cited material or information contained in the text should not be understood as a concession that the material or information was part of the common general knowledge or was known in Australia or any other country.

SUMMARY OF THE INVENTION

In one embodiment, the present invention seeks to provide an explosive storehouse for an earth covered magazine comprising:

-   -   a head wall;     -   a rear wall;     -   two side walls; and     -   a single span arched roof;     -   wherein the head wall, rear wall, two side walls and the single         span arched roof all include a metal lining located internally         of the earth covered magazine explosive storehouse; and     -   wherein at least the two side walls, rear wall and the single         span arched roof include shotcrete.

The metal lining allows the shotcrete formed behind it to be formed in a profile to minimise risk associated with the shotcrete in the event of an explosion. For example including recesses to encourage the shotcrete to fragment.

Shotcreting the walls against a metal lining allows the explosive storehouse to be formed quickly compared with conventional methods.

Preferably, the two side walls are straight side walls.

Straight side walls allows more explosives to be stored on the same footprint than for a conventional arched design.

Preferably, the head wall, the rear wall, the two side walls and the single span arched roof include concrete reinforcement bars.

Preferably, a bracket connects the metal lining of each of the two side walls to the metal lining of the single span arched roof.

In a second embodiment, the present invention seeks to provide a method of forming an explosive storehouse for an earth covered magazine including the steps of:

-   -   standing two straight metal linings opposite each other;     -   raising an arched internal single span metal lining to span         between the two straight metal linings at the top edges of the         two straight metal linings;     -   raising metal linings for head and rear walls at opposing ends         of the two straight metal linings;     -   forming and pouring a concrete floor;     -   placing internal propping between a connection between the         arched internal single span metal lining and each of the two         straight metal sides;     -   placing additional propping between the arched internal single         span metal lining and the floor;     -   placing a reinforcement bar adjacent the two straight metal         linings, the arched internal single span metal lining and         formwork for the head and rear walls;     -   pouring concrete into the formwork of the head wall to form a         concrete head wall; and     -   shotcrete the formwork of the rear wall to form a shotcrete rear         wall, shotcrete the two straight metal linings and shotcrete the         arched internal single span metal lining.

Preferably, the method includes a bracket between the arched internal single span metal lining and each of the two straight metal sides.

Preferably, the bracket is attached to the propping between the connection between the arched internal single span metal lining and each of the two straight metal linings during formation.

Preferably, the headwall is formed first after the floor is formed:

-   -   wherein the rear wall is shotcrete after the headwall is formed         followed by shotcreting a six metre wide strip at the top of the         arched internal single span metal lining from the rear wall to         the head wall;     -   wherein concrete formation is halted for at least a day         following the shotcreting the six metre strip; and     -   wherein after the at least one day half of one of the two         straight metal lining is shotcrete followed by shotcreting half         of the opposite of the two straight metal linings followed by         shotcreting the remaining half of the initially shotcrete one of         the two straight metal linings followed by shotcreting the         remaining half of the opposite of the two straight metal         linings.

Performing the steps in this order ensures structural stability during construction and a good curing for strength whilst allowing fast formation of the explosive storehouse.

BRIEF DESCRIPTION OF THE FIGURES

Further features of the present invention are more fully described in the following description of a non-limiting embodiment thereof. This description is included solely for the purposes of exemplifying the present invention. It should not be understood as a restriction on the broad summary, disclosure or description of the invention as set out above. The description will be made with reference to the accompanying drawings in which:

FIG. 1 is a front on view of a prior art explosive storehouse;

FIG. 2 is a front on section view of an explosive storehouse in accordance with an embodiment of the present invention;

FIG. 3 is a side section view of the explosive storehouse of FIG. 2;

FIG. 4 is a section view of the explosive storehouse propping arrangement of FIG. 2;

FIG. 5 is a perspective view of a wall and roof section of the explosive storehouse of FIG. 2 during construction;

FIG. 6 is a perspective view of the wall and roof connection of the wall and roof section of FIG. 5;

FIG. 7 is a side view of a bracket used between the wall and roof section of FIG. 5; and

FIG. 8 is a side view of a bracket used between the wall and roof section of FIG. 5.

In the drawings like structures are referred to by like numerals throughout the several views. The drawings shown are not necessarily to scale, with emphasis instead generally being placed upon illustrating the principles of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Broadly, the present invention relates to an arched roof 16 explosive storehouse 10 with straight wall sections 15. The straight wall sections 15 allow the floor space of the explosive storehouse 10 to be fully used and for easier access to store explosives, than an arched structure.

Referring to FIG. 1, a prior art arched roof earth covered magazine ESH explosive storehouse 01 is shown. This type of ESH uses a single span arched roof 03 covered in a mound 12 of earth 05. Doors 06 provide access to the explosive storehouse 01. The single span arched roof connects to the ground 09 at fixing points 08. In cooperation with the mound 12 of earth 05, the single span arched roof 03 attenuate explosions that occur within the prior art arched roof ESH 01 and direct the explosion towards the crown 04 of the igloo 01. Due to the single span arched roof 03 making up the roof and side walls side space 02 is left that cannot receive explosives as they cannot be reached with lifting and transportation tools such as forklifts due to the height of the roof in this region.

With reference to FIGS. 2 and 3, a straight wall arched roof ESH 10 accord to an embodiment of the present invention is illustrated. The straight wall arched roof ESH 10 includes straight walls 55 and a single span arched roof 16 connected to the straight walls to define an internal space 14 for storage of explosives 11. The straight walls 55 include reinforced shotcrete wall portion 15 and a straight metal lining 39 connected to the reinforced shotcrete wall section 15. The single span arched roof 16 includes a single span reinforced shotcrete section 17 and an internal arched single span metal lining 13 abutting the single span reinforced shotcrete section 17. The straight side walls 55 ensure that explosives 11 can be stored proximate the straight side walls 55. This allows the explosives 11 to be stored closer to the straight side walls 55 than they could be stored near the ground connection in a single span arched structure as described in FIG. 1.

The straight walled arched roof ESH 10 includes a roof vent 18 and is covered by soil mound 12 to assist in containing and resisting explosions. The straight side walls 55 are attached to the ground 09 at concrete foundation 20. The straight walled ESH 10 also includes a head wall 19 with doors and a rear wall 49. The head wall 19 and rear wall 49 are also metal lined. Metal lining the entire perimeter of the ESH 10 above the floor allows the metal to be shaped to dictate the profile of the concrete formed for the walls. This shape can be chosen to influence the blast and debris explosion pattern in the event of an explosion. For panel jointing in the metal lining is to encourage concrete not to form large fragments in the event of an explosion.

With reference to FIGS. 4 to 7, a method of forming the straight walled arched roof ESH 10 of FIGS. 2 and 3 will be described.

Sets of straight metal linings 39 are raised in opposing positions in the location where the walls of the straight walled arched roof ESH 10 are to be and external props 21 are placed against it to keep it plumb and in place. External props 21 are attached to the straight metal linings 39 at one end and to temporary concrete blocks 60 on the other end at the ground to support the external props 21 and straight metal linings 39.

With the straight metal linings 39 in opposing position propped in place the arched internal single span metal lining 13 is raised into place on top of the straight metal linings 39 of the straight walled arched roof ESH 10 and connected to bracket 29. Straight metal linings are installed to front and rear walls. Reinforcement bars for the floor are put in place and concrete for the foundation and floor of the straight walled arch roof ESH 10 is poured and left to set. Reinforcement is then put in place for the head wall 19, formwork for the head wall is then put in place and the head wall is poured with concrete over the reinforcement, within formwork, to form the headwall 19.

Internal props 24 abut the bracing angles 25 and are supported by the ground or set concrete floor. Internal props 24 engage with bracing angles 25 with the arched internal single span metal lining 13 supported with props. Reinforcement bars 23 are placed around both the straight metal linings 39, the metal linings of rear wall 49, and the arched internal single span metal lining 13.

The rear wall 49 is shotcreted at a constant thickness. Then the straight metal linings 39 are shotcreted over the reinforcement bars 23 to form reinforced shotcrete wall portion 15. Then the arched internal single span metal lining 13 is shotcreted over the reinforcement bars 23 to form single span reinforced shotcrete section 17.

When the shotcrete sets the straight metal linings 39 and reinforced shotcrete wall portion 15 form straight walls 55 and the arched internal single span metal lining 13 and single span reinforced shotcrete section 17 form single span arched roof 16.

In one embodiment, when the straight metal linings 39 and the arched internal single span metal lining 13 are propped and ready for concrete with reinforcement bars 23 in place, shotcreting is performed in a particular sequence to maximise the stability and strength of the structure.

Firstly the rear wall 49 is shotcreted and a strip six metres wide at the top of the arched internal single span metal lining 13 from the rear wall 49 to the head wall 19 is shotcreted. At this stage shotcreting and conventional concrete pouring is halted for at least one day.

After one day half of the straight metal linings 39 is shotcreted followed by shotcreting half the opposite straight metal linings 39. Then the initially sprayed straight metal lining 39 has the remaining half shotcreted followed by the remaining half of the opposite side straight metal lining 39.

With specific reference to FIG. 7, in one embodiment the bracing angles 25 include a reinforcing bracket 30 comprising a first plate 45 and a second plate 35. The second plate 35 is longer than the first plate 45. The bracing angles 25 also include small fixing bracket 27 extending from the first plate 45 and large fixing brackets 29 extending from the second plate 35. Small fixing brackets 27 are designed to fix the top of the straight metal linings 39. Large fixing brackets 29 are designed to fix the arched internal single span metal lining 13 to abut the end of the straight metal linings 39.

A further embodiment of the bracing angle 25 alternative bracing angle 65 is illustrated in FIG. 8. For convenience features of the further embodiment of the alternative bracing angle 65 that are similar or correspond to features of the bracing angle 25 of FIG. 7 have been referenced with the same reference numerals. The bracing angles 65 include a reinforcing bracket 30 comprising a first plate 45 and a second plate 35. The second plate 35 is longer than the first plate 45. The bracing angles 25 also include first fixing bracket 67 extending from the first plate 45 and second fixing bracket 69 extending from the second plate 35. First fixing bracket 67 is designed to sit at the end of the bracing angles 25 to abut the end of the arched internal single span metal lining 13. Second fixing brackets 69 is designed to sit at the end of the bracing angles 25 to abut the end of the straight metal linings 39.

VARIATIONS AND MODIFICATIONS

Modifications and variations such as would be apparent to the skilled addressee are considered to fall within the scope of the present invention. The present invention is not to be limited in scope by any of the specific embodiments described herein. These embodiments are intended for the purpose of exemplification only. Functionally equivalent products, formulations and methods are clearly within the scope of the invention as described herein.

Throughout this specification, unless the context requires otherwise, the word “comprise” or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

Any reference to prior art contained herein is not to be taken as an admission that the information is common general knowledge, unless otherwise indicated. 

1. An explosive storehouse comprising: a head wall; a rear wall; two side walls; and a single span arched roof; wherein the head wall, rear wall, two side walls and the single span arched roof all include a metal lining located internally of the earth covered magazine explosive storehouse; and wherein at least the two side walls, rear wall and the single span arched roof include shotcrete.
 2. The explosive storehouse as claimed in claim 1, wherein the two side walls are straight side walls.
 3. The explosive storehouse as claimed in claim 1, wherein the head wall, a rear wall, two side walls and a single span arched roof include reinforcement bars.
 4. The explosive storehouse as claimed in claim 1, wherein the side and rear walls and roof include shotcrete.
 5. The explosive storehouse as claimed in claim 1, wherein a bracket connects the metal lining of each of the two side walls to the metal lining of the single span arched roof.
 6. A method of forming an explosive storehouse including the steps of: standing two straight metal linings opposite each other and supporting the two straight metal linings with props; raising an arched internal single span metal lining to span between the two straight metal linings at the top edges of the two straight metal linings; raising metal linings for head and rear walls at opposing ends of the two straight metal linings; forming, pouring and setting a concrete floor; placing internal propping between a connection between the arched internal single span metal lining and each of the two straight metal sides; placing additional framework between the arched internal single span metal lining and the floor; placing a reinforcement bar adjacent the two straight metal linings, the arched internal single span metal lining and for the head and rear walls; placing formwork to the head wall; pouring concrete into the formwork of the head wall to form a concrete head wall; and shotcrete the formwork of the rear wall to form a shotcrete rear wall, shotcrete the two straight metal linings and shotcrete the arched internal single span metal lining.
 7. The method of forming an explosive storehouse as claimed in claim 6, including a bracket between the arched internal single span metal lining and each of the two straight metal sides
 8. The method of forming an explosive storehouse as claimed in claim 7, wherein the bracket is attached to the propping between the connection between the arched internal single span metal lining and each of the two straight metal linings during formation.
 9. The method of forming an explosive storehouse as claimed in claim 6: wherein the headwall is formed first after the floor is formed; wherein the rear wall is shotcrete after the headwall is formed followed by shotcreting a six metre wide strip at the top of the arched internal single span metal lining from the rear wall to the head wall; wherein concrete formation is halted for at least a day following the shotcreting the six metre strip; and wherein after the at least one day half of one of the two straight metal lining is shotcrete followed by shotcreting half of the opposite of the two straight metal linings followed by shotcreting the remaining half of the initially shotcrete one of the two straight metal linings followed by shotcreting the remaining half of the opposite of the two straight metal linings. 